Stereoselectivity in mammalian chemical communication: Male mouse pheromones

Two male mouse pheromones, 3,4-dehydro-exo-brevicomin (DHB) and 2-sec-butyldihydrothiazole (SBT), are chiral molecules which were previously tested in their respective bioasays as racemic mixtures. The focus of this study has been to determine the absolute configuration of their natural forms and its relation to stereospecific biological action. DHB was established as the R,R-enantiomer possessing biological activity. Due to an extremely easy racemization of SBT under very mild conditions, enantioselectivity of its transmission and its action at the receptor site appear to be of secondary importance.     

Chiral influence of sex pheromonal substances on responses of the male American cockroach

Summary In order to elucidate the roles of optical enantiomers of sex pheromonal substances of the American cockroach, behavioral assays with a single enantiomer and with mixtures of enantiomers of sex pheromone mimics were carried out. Inactive enantiomers [(–)-enantiomers] had no influence on the potency of enantiomers active as sex pheromones [(+)-enantiomers]. By analysis of the results from EAG recordings with single and mixed sample of the enantiomers, it was confirmed that (–)-enantiomers did not react with the sex pheromone receptors which are responsive to (+)-enantiomers.We acknowledge technical assistance from Miss R. Kimura.     

蚁群算法求解旅行商问题若干改进策略的研究

蚁群算法是求解TSP问题的一个性能较好的仿生型的智能优化算法,但存在着运行时间长、容易陷入局部最优的缺点,导致停滞现象的出现,找不到全局最优解.实验表明,使用候选集合策略和局部搜索策略能提高算法所求得的解的质量,同时也会明显加快求解的速度.使用信息素变异和重新初始化策略,能增加路径探索的多样性,使算法对搜索空间的探索始终保持在一个合理的水平上,有效地避免算法陷入停滞状态,从而找到全局最优解.     

蚁群算法求解TSP问题若干改进策略的研究

蚁群算法是求解TSP问题的一个性能较好的仿生型的智能优化算法,但存在着运行时间长、容易陷入局部最优的缺点,导致停滞现象的出现,找不到全局最优解.实验表明,使用候选集合策略和局部搜索策略能提高算法所求得的解的质量,同时也会明显加快求解的速度.使用信息素变异和重新初始化策略,能增加路径探索的多样性,使算法对搜索空间的探索始终保持在一个合理的水平上,有效地避免算法陷入停滞状态,从而找到全局最优解.     

啮齿动物性识别外激素的研究概况及方法

啮齿动物普遍利用外激素进行性识别。具有性识别功能的外激素可能由身体各个发出气味的部位产生,例如,尿液、粪便、唾液、精液、胚胎液、阴道分泌物、特化皮肤腺分泌物等。外激素的产生器官,尤其特化皮肤腺的形态、组织结构、所产生的化学成分和性识别功能有季节和性别的差异,并且受到脑垂体、内分泌腺和性腺分泌激素的调节。确定气味的识别功能和产生源,常利用被试鼠对雌雄气味的行为反应差异;生理调节作用的研究常采用切除有关的激素分泌腺和植入外源的激素后,气味产生器官的形态、组织结构和分泌物化学成分,以及对气味的嗅觉反应的变化的方法;化学研究涉及到气味分析样品的制备和对样品进行化学分析,进一步的活性成分的鉴定还要和生物测定相结合。     

Baker酵母用于光学活性昆虫性信息素的合成方法述评

通过综述近１０年来Ｂａｋｅｒ酵母用于不对称合成的研究十分活跃的状况，介绍了它在制备高光学活性手性化合物的发展近况，着重评述了Ｂａｋｅｒ酵母作用特点及其在合成光学学活性昆虫性信息素中的应用。     

Volatiles from clover headHypera meles (Fab.) and alfalfaH. postica (Gyllenhal) weevils: search for pheromones

Summary Volatile fractions of the clover head,Hypera meles (Fab.), and alfalfa,Hypera postica (Gyllenhal), weevils contained three of four boll weevil,Anthonomus grandis (Boh.), pheromone components, (Z)-3,3-dimethylcyclohexane ^1,-ethanol and (Z)- and (E)-3,3-dimethylcyclohexane-^1,-acetaldehyde. Also found were eight oxygenated monoterpenes, previously identified as precursors and intermediates of the boll weevil pheromones.     

Sexual behavior mutants revisited: molecular and cellular basis of Drosophila mating

The study of Drosophila melanogaster by a combination of forward genetics with specific mutants, and reverse genetics, in which a given gene is expressed in an appropriate brain area to test its effect on behavior, provides a unique opportunity to explore the causal relationship between a particular gene, its function in the cell and the behavioral outcome at the organismic level. Enhanced male-to-male courtship has been shown to occur as a result of mutations in several different genes. For example, the Voila mutant exhibits intense GAL4 reporter expression in the tarsal gustatory sensilla, suggesting the importance of tapping by a male on the female abdomen with his forelegs. Feminization of parts of the antennal lobe and mushroom body by targeted expression of a female-determining gene transformer ⁺ (tra ⁺) drives the male to court other males. Mutations in the tra target gene fruitless (fru), which is expressed in the antennal lobe as well as the suboesophageal ganglion (the gustatory inputs are processed here), also induce homosexual courtship in males. These results suggest that sensory inputs mediated and/or processed by the tarsal receptors, suboesophageal ganglion, antennal lobe and mushroom body contribute to the regulation of male–female courtship. Mosaic analysis localized the neural center for male courtship behavior to the posterior dorsal brain, in which the sensory information processed by the aforementioned neural structures may be integrated. Another mosaic study mapped the neural center for female sexual behavior, as measured by her receptiveness to copulation, to the anterior dorsal brain. The issue as to how the mutations that reduce female sexual receptiveness, e.g. dissatisfaction (dsf), spinster (spin) and chaste (cht), affect the structure and/or function of this neural center deserves to be addressed urgently. Received 27 April 1999; received after revision 21 June 1999; accepted 8 July 1999     

Soluble proteins in insect chemical communication

Our understanding of the biochemical mechanisms that mediate chemoreception in insects has been greatly improved after the discovery of olfactory and taste receptor proteins. However, the presence of soluble polypeptides in high concentration around the dendrites of sensory neurons still poses unanswered questions. More than 2 decades after their discovery and despite the wealth of structural information available, the physiological function of odorant-binding proteins is not well understood. More recently, members of a second family of soluble polypeptides, the chemosensory proteins, were also discovered in the lymph of chemosensilla. Here we review the structural properties of both classes of soluble proteins, their affinity to small ligands, and their expression in the different parts of the insect body and subcellular localisation. Finally, we discuss current ideas and models of the role of such proteins in insect chemoreception. Received 27 December 2005; received after revision 6 March 2006; accepted 13 April 2006     

Alarm pheromones from the Mediterranean opisthobranchHaminoea navicula

Summary Structure and absolute stereochemistry of two new 3-alkylpyridines, haminol-A (3) and haminol-B (4), isolated from the cephalaspidean molluscHaminoea navicula, have been determined by means of spectral and chemical methods. Haminols are secreted byH. navicula when it is molested, and these induce an alarm response in trail-following conspecifics.In part presented at the 32nd IUPAC Congress Stockholm, 2–7 August 1989. Cimino, G., and Sodano, G., Abstracts SL 302, p. 63.